OBJECTIVE: Long-term fasting (LF) is increasingly emerging as a non-pharmacological approach to modulate risk factors associated with the development of atherosclerotic cardiovascular diseases (ASCVD). However, protection from ASCVD is more tied to the functionality of high-density lipoprotein (HDL) than its plasma levels. Our prospective interventional study focuses on the functional properties of lipoproteins in modulating cholesterol homeostasis on peripheral cells and examines how LF may influence this and lipoprotein subclass composition. For that purpose, we investigated its impact on HDL-cholesterol efflux capacity (CEC), and on serum cholesterol loading capacity (CLC).
METHODS: Forty healthy subjects (50 % females) underwent medically supervised 9-day fasting (250 kcal/day) in a specialised facility. Thirty-two subjects had a follow-up examination after one month of food reintroduction.
RESULTS: LF was well tolerated and increased self-reported energy levels. Fasting reduced triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and HDL cholesterol (HDL-C). Very-low-density lipoprotein cholesterol (VLDL-C) and LDL3-C showed sustained reductions at follow-up. Only HDL-C, specifically HDL2-C levels, increased at follow-up. Total HDL-CEC decreased during LF and increased above baseline at follow-up. Fasting decreased ATP binding cassette (ABC)A1-mediated HDL-CEC whereas ABCG1-mediated HDL-CEC remained unaffected. Aqueous diffusion increased at follow up. LF decreased serum CLC and then returned to baseline levels.
CONCLUSIONS: LF not only maintains lipoprotein functionality but also contributes to a favorable shift in the atherogenic risk profile, which persists even after food reintroduction. This further emphasizes the importance of considering HDL functionality alongside traditional lipid measurements to understand the potential for non-pharmacological interventions like LF to promote cardiovascular prevention and health.
BACKGROUND: NCT05031598.

UNASSIGNED: To determine the relationship between lipoprotein particle size/number with hepatic steatosis (HS), given its association with traditional lipoproteins and coronary atherosclerosis.
UNASSIGNED: Individuals with available CT data and blood samples enrolled in the PROMISE trial were studied. HS was defined based on CT attenuation. Lipoprotein particle size/number were measured by nuclear magnetic resonance spectroscopy. Principal components analysis (PCA) was used for dimensionality reduction. The association of PCA factors and individual lipoprotein particle size/number with HS were assessed in multivariable regression models. Associations were validated in an independent cohort of 59 individuals with histopathology defined HS.
UNASSIGNED: Individuals with HS (n=410/1,509) vs those without (n=1,099/1,509), were younger (59±8 vs 61±8 years) and less often females (47.6 % vs 55.9 %). All PCA factors were associated with HS: factor 1 (OR:1.36, 95 %CI:1.21-1.53), factor 3 (OR:1.75, 95 %CI:1.53-2.02) and factor 4 (OR:1.49; 95 %CI:1.32-1.68) were weighted heavily with small low density lipoprotein (LDL) and triglyceride-rich (TRL) particles, while factor 2 (OR:0.86, 95 %CI:0.77-0.97) and factor 5 (OR:0.74, 95 %CI:0.65-0.84) were heavily loaded with high density lipoprotein (HDL) and larger LDL particles. These observations were confirmed with the analysis of individual lipoprotein particles in PROMISE. In the validation cohort, association between HS and large TRL (OR: 8.16, 95 %CI:1.82-61.98), and mean sizes of TRL- (OR: 2.82, 95 %CI:1.14-9.29) and HDL (OR:0.35, 95 %CI:0.13-0.72) were confirmed.
UNASSIGNED: Large TRL, mean sizes of TRL-, and HDL were associated with radiographic and histopathologic HS. The use of lipoprotein particle size/number could improve cardiovascular risk assessment in HS.

Metabolic syndrome (MS) is a widespread disease in developed countries, accompanied, among others, by decreased adiponectin serum levels and perturbed lipoprotein metabolism. The associations between the serum levels of adiponectin and lipoproteins have been extensively studied in the past under healthy conditions, yet it remains unexplored whether the observed associations also exist in patients with MS. Therefore, in the present study, we analyzed the serum levels of lipoprotein subclasses using nuclear magnetic resonance spectroscopy and examined their associations with the serum levels of adiponectin in patients with MS in comparison with healthy volunteers (HVs). In the HVs, the serum levels of adiponectin were significantly negatively correlated with the serum levels of large buoyant-, very-low-density lipoprotein, and intermediate-density lipoprotein, as well as small dense low-density lipoprotein (LDL) and significantly positively correlated with large buoyant high-density lipoprotein (HDL). In patients with MS, however, adiponectin was only significantly correlated with the serum levels of phospholipids in total HDL and large buoyant LDL. As revealed through logistic regression and orthogonal partial least-squares discriminant analyses, high adiponectin serum levels were associated with low levels of small dense LDL and high levels of large buoyant HDL in the HVs as well as high levels of large buoyant LDL and total HDL in patients with MS. We conclude that the presence of MS weakens or abolishes the strong associations between adiponectin and the lipoprotein parameters observed in HVs and disturbs the complex interplay between adiponectin and lipoprotein metabolism.

To investigate the plasma lipoprotein subclasses in patients with primary open-angle glaucoma (POAG), a total of 20 Chinese POAG patients on intraocular pressure (IOP)-lowering treatment and 20 age-matched control subjects were recruited. Based on the levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), the study subjects were divided into elevated- and normal-level subgroups. The plasma lipoprotein, lipoprotein subclasses, and oxidized LDL (oxLDL) levels were quantitatively measured. The discrimination potential of the lipoproteins was evaluated using the area under the receiver operating characteristic curve (AUC), and their correlation with clinical parameters was also evaluated. Compared to the control subjects with elevated TC and/or LDL-C levels, the levels of TC, LDL-C, non-high-density lipoprotein cholesterol (non-HDL), LDL subclass LDL3 and small dense LDL (sdLDL), and oxLDL were significantly higher in POAG patients with elevated TC and/or LDL-C levels. No differences in any lipoproteins or the subclasses were found between the POAG patients and control subjects with normal TC and LDL-C levels. Moderate-to-good performance of TC, LDL-C, non-HDL, LDL3, sdLDL, and oxLDL was found in discriminating between the POAG patients and control subjects with elevated TC and/or LDL-C levels (AUC: 0.710-0.950). Significant negative correlations between LDL3 and sdLDL with retinal nerve fiber layer (RNFL) thickness in the superior quadrant and between LDL3 and average RNFL thickness were observed in POAG patients with elevated TC and/or LDL-C levels. This study revealed a significant elevation of plasma lipoproteins, especially the LDL subclasses, in POAG patients with elevated TC and/or LDL-C levels, providing insights on monitoring specific lipoproteins in POAG patients with elevated TC and/or LDL-C.

Plasma lipid levels are commonly measured using traditional methods such as triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and cholesterol (CH). However, the use of newer technologies, such as nuclear magnetic resonance (NMR) with post-analysis platforms, has made it easier to assess lipoprotein profiles in research. In this study involving ApoE-deficient mice that were fed high-fat diets, significant changes were observed in TG, CH, free cholesterol (FC), and phospholipid (PL) levels within the LDL fraction. The varied proportions of TG in wild-type mice and CH, FC, and PL in ApoE-/- mice were strikingly different in very low-density lipoproteins (VLDL), LDL, intermediate-density lipoprotein (IDL), and HDL. This comprehensive analysis expands our understanding of lipoprotein subfractions and the impacts of the APOE protein and high-fat diet in mouse models. The new testing method allows for a complete assessment of plasma lipids and their correlation with genetic background and diet in mice.

BACKGROUND: The association between lipoprotein subclasses and carotid intima-media thickness (cIMT) progression has yet to be fully evaluated. We assessed which lipoprotein subclasses were associated with maximum cIMT levels in the general population.
METHODS: In this study, cholesterol and triglyceride content of 20 lipoprotein subclasses were analyzed using gel permeation high-performance liquid chromatography (GP-HPLC) in 864 Japanese women and men (mean age 57 y, free of chronic liver or kidney diseases and off lipid-lowering, hormone replacement, or adrenocorticosteroid medications). Univariate and multivariate regression analyses and univariate and partial correlation analyses were performed to examine the relationships between lipoprotein subclasses and maximum cIMT levels.
RESULTS: After adjusting for age, sex, systolic blood pressure, smoking, diabetes, and anti-hypertensive agents, elevated low-density lipoprotein (LDL)-2 and -3 cholesterol (particle diameter 25.5 nm and 23.0 nm, respectively; medium and small LDL) were associated with higher maximum cIMT levels in both women and men (all p for trend < 0.05). These associations were significant even after participants taking anti-diabetic or anti-hypertensive agents were excluded. No significant associations were found between any triglyceride subclasses and maximum cIMT levels.
CONCLUSIONS: Smaller LDL particle cholesterol values are the most atherogenic lipoprotein parameter.

The association between serum levels of endothelial lipase (EL) and the serum levels and composition of apolipoprotein B (apoB)-containing lipoproteins in healthy subjects and patients with metabolic syndrome (MS) remained unexplored. Therefore, in the present study, we determined the serum levels and lipid content of apoB-containing lipoproteins using nuclear magnetic resonance (NMR) spectroscopy and examined their association with EL serum levels in healthy volunteers (HVs) and MS patients. EL was significantly negatively correlated with the serum levels of cholesterol in large very low-density lipoprotein (VLDL) particles, as well as with total-cholesterol-, free-cholesterol-, triglyceride-, and phospholipid-contents of VLDL and intermediate-density lipoprotein particles in MS patients but not in HVs. In contrast, EL serum levels were significantly positively correlated with the serum levels of apoB, triglycerides, and phospholipids in large low-density lipoprotein particles in HVs but not in MS patients. EL serum levels as well as the serum levels and lipid content of the majority of apoB-containing lipoprotein subclasses were markedly different in MS patients compared with HVs. We conclude that EL serum levels are associated with the serum levels and lipid content of apoB-containing lipoproteins and that these associations are markedly affected by MS.

OBJECTIVE: Prevention measures for cardiovascular diseases (CVD) have shifted their focus from lipoproteins to the immune system. However, low-grade inflammation and dyslipidemia are tightly entangled. The objective of this study was to assess the relations between a broad panel of inflammatory biomarkers and lipoprotein subclass parameters.
METHODS: We utilized data from the population-based Study of Health in Pomerania (SHIP-TREND, n = 403). Plasma concentrations of 37 inflammatory markers were measured by a bead-based assay. Furthermore, we employed nuclear magnetic resonance spectroscopy to measure total cholesterol, total triglycerides, total phospholipids as well as the fractional concentrations of cholesterol, triglycerides, phospholipids, ApoA1, ApoA2 and ApoB in all major lipoprotein subclasses. Associations between inflammatory biomarkers and lipoprotein subclasses were analyzed by adjusted linear regression models.
RESULTS: APRIL, BAFF, TWEAK, sCD30, Pentraxin-3, sTNFR1, sTNFR2, Osteocalcin, Chitinase 3-like 1, IFN-alpha2, IFN-gamma, IL-11, IL-12p40, IL-29, IL-32, IL-35, TSLP, MMP1 and MMP2 were related with lipoprotein subclass components, forming two distinct clusters. APRIL had inverse relations to HDL-C (total and subclasses) and HDL Apo-A1 and Apo-A2 content. MMP-2 was inversely related to VLDL-C (total and subclasses), IDL-C as well as LDL5/6-C and VLDL-TG, IDL-TG, total triglycerides as well as LDL5/5-TG and HDL4-TG. Additionally, we identified a cluster of cytokines linked to the Th1-immune response, which were associated with an atherogenic lipoprotein profile.
CONCLUSIONS: Our findings expand the existing knowledge of inflammation-lipoprotein interactions, many of which are suggested to be involved in the pathogeneses of chronic non-communicable diseases. The results of our study support the use of immunomodulatory substances for the treatment and possibly prevention of CVD.

Telomere length (TL) is a well-known marker of age-related diseases. Oxidative stress and inflammation increase the rate of telomere shortening, triggering cellular senescence. Although lipoproteins could have anti-inflammatory and proinflammatory functional properties, the relationship between lipoprotein particles with TL and telomerase activity-related genes has not been investigated much. In this study, we assessed the associations of lipoprotein subfractions with telomere length, TERT, and WRAP53 expression in a total of 54 pre-diabetic subjects from the EPIRDEM study. We regressed TL, TERT, and WRAP53 on 12 lipoprotein subclasses, employing a Gaussian linear regression method with Lasso penalty to determine a lipoprotein profile associated with telomere-related parameters. The covariates included age, sex, body mass index (BMI), dyslipidemia, statin consumption, and physical activity leisure time. We identified a lipoprotein profile composed of four lipoprotein subfractions associated with TL (Pearson r = 0.347, p-value = 0.010), two lipoprotein subfractions associated with TERT expression (Pearson r = 0.316, p-value = 0.020), and five lipoprotein subfractions associated with WRAP53 expression (Pearson r = 0.379, p-value =0.005). After adjusting for known confounding factors, most lipoprotein profiles maintained the association with TL, TERT, and WRAP53. Overall, medium and small-sized HDL particles were associated with shorter telomeres and lower expression of TERT and WRAP53. Large HDL particles were associated with longer telomere and lower expression of WRAP53, but not with TERT. Our results suggest that the lipoprotein profiles are associated with telomere length, TERT, and WRAP53 expression and should be considered when assessing the risk of chronic diseases.

People with type 1 diabetes (T1D) present lipoprotein disturbances that could contribute to their increased cardiovascular disease (CVD) risk. We evaluated the relationship between lipoprotein alterations and atherosclerosis in patients with T1D.
Cross-sectional study in subjects with T1D, without previous CVD, but high-risk (≥40 years, nephropathy, or ≥10 years of evolution of diabetes with another risk factor). The presence of plaque (intima-media thickness ≥1.5 mm) in the different carotid segments was determined by ultrasound. The advanced lipoprotein profile was analysed by magnetic resonance imaging (1H NMR). We included 189 patients (42% women, 47.8 ± 10.7 years, duration of diabetes 27.3 ± 10.1 years, HbA1c 7.5% [7-8]). Those with carotid plaques (35%) were older, with longer diabetes duration, had a higher prevalence of hypertension, and showed lower and smaller LDL particles (LDL-P) and HDL particles (HDL-P), but higher VLDL particles (VLDL-P). Some LDL, HDL and VLDL-related parameters were associated with atherosclerosis in sex, age and statin use adjusted models (p < 0.05), but after adjusting for multiple confounders, including conventional lipid parameters, only HDL-P (OR 0.440 [0.204-0.951]; p = 0.037), medium HDL-P (OR 0.754 [0.590-0.963]; p = 0.024), HDL-P cholesterol content (OR 0.692 [0.495-0.968]; p = 0.032), 1H NMR LDL-P number/conventional LDL-cholesterol (OR 1.144 [1.026-1.275]; p = 0.015), and 1H NMR non-HDL particle number/conventional non-HDL-cholesterol ratios (OR 1.178 [1.019-1.361], p = 0.026) remained associated with atherosclerosis.
In adults with T1D at high-risk, variables related to HDL, LDL and total atherogenic particle number are independently associated with preclinical atherosclerosis. Advanced lipoprotein profiling could be used to identify those at the highest risk of CVD.